In the prior art, a technique is available to correct an image of a person as an object by which the skin of the object looks smooth and beautiful. As a specific example of this image correction, a technique for locally shading off the edges or the brightness difference of the whole image or gradating the area of the skin color component of the whole image by using a ε-filter (for example, see Patent Document 1).
Also, as a technique intended to correct or remove the undesired components such as wrinkles, spots, rough dry skin or pimples included in a face image, the following technique is available (see Patent Document 2).
First, in respect of a signal value of each pixel forming an image of a face mainly, a signal level difference of each pixel with each surrounding pixel is detected by a difference detector. This signal level difference is compared with a reference value by a threshold determining unit. In accordance with the result of this comparison, an arithmetic unit multiplies the signal level difference by a predetermined coefficient, which is added to each pixel value. From the result of this addition, the reference value for comparison and the coefficient for the multiplier are selected in accordance with the pixel position and the image. In this way, an image free of the undesired components included in the face image is obtained.
As another conventional technique, a human image processing apparatus is available by which a decoration can be added to the body portion of a human image, or especially, the face portion or the head portion without any superposition of decorations (see Patent Document 3). This human image processing apparatus comprises a means for setting the position and the range of a body portion area based on at least one element making up the body portion of a human image, and a means for adding a decoration only to the background area other than the body portion area. Also, this human image processing apparatus may comprise a means for setting the position and the range of the body portion area based on at least one element making up the body portion of a human image and a means for adding a decoration along the outer periphery of the body portion area.    [Patent Document 1]    U.S. Pat. No. 3,319,727    [Patent Document 2]    Japanese Unexamined Patent Publication No. 2000-105815    [Patent Document 3]    Japanese Unexamined Patent Publication No. 2000-022929